Why Thick Black Carbon Build Up on Water Heater Burner

[StudiousGeek]

Anyone have any idea why I keep getting this thick Black Carbon Build-Up on Water Heater Burner? (see Pic)

 

[SHEPLMBR]

How old is the heater? Are you on Natural gas or propane?

 

[FishScreener]

The mixture is rich. Either the air feed is blocked, or you have the wrong jet for the elevation/fuel. Most natural gas units can be rejetted for LPG(Propane), and both can be rejetted for elevation. But if it isn’t done you get the carburizing flame you have evidenced by the carbon build up on the burner. IIRC, a carburizing flame produces far more carbon-monoxide, and burns considerably more gas, so you really need to get it sorted soon.